Stationary guide vanes and rotating turbine blades in gas turbines often have internal cooling channels. Cooling effectiveness is important in order to minimize thermal stress on these airfoils. Cooling efficiency is important in order to minimize the volume of air diverted from the compressor for cooling.
One cooling technique uses serpentine cooling channels with turbulators. An example is shown in U.S. Pat. No. 6,533,547. The present invention provides improved turbulators with features at multiple scales in combinations that increase surface area, increase boundary layer mixing, and control boundary layer separation.